Allow an environment to define only onExit

crates/openjd-model/src/template/validate_v2023_09/mod.rs

@@ -99,11 +99,12 @@ pub struct EffectiveRules {
     pub allowed_job_param_types: std::collections::HashSet<JobParameterType>,
     pub allowed_task_param_types: std::collections::HashSet<TaskParameterType>,
     pub allow_fmtstring_in_numeric_fields: bool,
-    /// When the `WRAP_ACTIONS` extension is enabled, an environment script
-    /// is valid if it defines any of `onEnter`, `onExit`, or one of the
-    /// RFC 0008 wrap hooks (`onWrapEnvEnter`, `onWrapTaskRun`, `onWrapEnvExit`).
-    /// Without the extension, the base 2023-09 rule applies:
-    /// `onEnter` is required whenever `script` is present.
+    /// An environment script must define at least one action whether or not
+    /// this flag is set, and either `onEnter` or `onExit` alone satisfies
+    /// that. The flag decides two things: whether the RFC 0008 wrap hooks
+    /// (`onWrapEnvEnter`, `onWrapTaskRun`, `onWrapEnvExit`) also count as an
+    /// acceptable choice, and which wording the error uses when no action is
+    /// defined. It does not make `onEnter` required.
     pub wrap_actions_enabled: bool,
 }
 

crates/openjd-model/src/template/validate_v2023_09/structure.rs

@@ -389,29 +389,22 @@ pub fn validate_single_environment(
     if let Some(script) = &env.script {
         let script_path = path_field(path, "script");
         let actions_path = path_field(&script_path, "actions");
-        // Base 2023-09 requires `onEnter` whenever a `script` is present.
-        // RFC 0008 relaxes this: when `WRAP_ACTIONS` is enabled, an env may
-        // define only wrap hooks (or any single action) without a standalone
-        // `onEnter`. Concretely, require at least one of the five known
-        // actions to be present so we don't accept an empty `actions: {}`.
-        if rules.wrap_actions_enabled {
-            // RFC 0008: an env may define only wrap hooks (or any single
-            // action) without a standalone `onEnter`. Require at least one of
-            // the five known actions so an empty `actions: {}` is still
-            // rejected. The all-or-nothing wrap-hook rule (defining any wrap
-            // hook requires all three) is enforced separately in
-            // `wrap_actions.rs`, not here.
-            if !script.actions.has_any_action() {
-                errors.add(
-                    &actions_path,
-                    "must define at least one of onEnter or onExit, or the complete set of wrap hooks (onWrapEnvEnter, onWrapTaskRun, and onWrapEnvExit together).",
-                );
-            }
-        } else if script.actions.on_enter.is_none() {
-            // Preserve the original wording when the extension is not enabled
-            // so pre-RFC error messages don't change. `on_enter.is_none()`
-            // also covers the empty-`actions` case.
-            errors.add(&actions_path, "onEnter is required.");
+        // An environment script must define at least one action. Either
+        // `onEnter` or `onExit` alone satisfies this, so an environment whose
+        // only work is cleanup is valid. With `WRAP_ACTIONS` a complete set of
+        // wrap hooks also satisfies it. Requiring at least one of the five
+        // known actions is what rejects an empty `actions: {}`. The
+        // all-or-nothing wrap-hook rule (defining any wrap hook requires all
+        // three) is enforced separately in `wrap_actions.rs`, not here.
+        if !script.actions.has_any_action() {
+            errors.add(
+                &actions_path,
+                if rules.wrap_actions_enabled {
+                    "must define at least one of onEnter or onExit, or the complete set of wrap hooks (onWrapEnvEnter, onWrapTaskRun, and onWrapEnvExit together)."
+                } else {
+                    "must define at least one of onEnter or onExit."
+                },
+            );
         }
         for (name, action) in script.actions.iter_named() {
             validate_action(

crates/openjd-model/tests/integration/test_actions_and_steps.rs

@@ -296,7 +296,7 @@ fn test_env_actions_empty() {
     }"#;
     check_err(
         s,
-        &["jobEnvironments[0] -> script -> actions:\n\tonEnter is required."],
+        &["jobEnvironments[0] -> script -> actions:\n\tmust define at least one of onEnter or onExit."],
     );
 }
 
@@ -599,10 +599,9 @@ fn test_env_action_on_exit() {
         "steps": [{"name": "S", "script": {"actions": {"onRun": {"command": "foo"}}}}],
         "jobEnvironments": [{"name": "E", "script": {"actions": {"onExit": {"command": "foo"}}}}]
     }"#;
-    check_err(
-        s,
-        &["jobEnvironments[0] -> script -> actions:\n\tonEnter is required."],
-    );
+    // Either ordinary action alone is sufficient, so a cleanup-only
+    // environment is valid.
+    decode_ok(s);
 }
 
 #[test]

crates/openjd-model/tests/integration/test_environment_template.rs

@@ -744,18 +744,41 @@ fn test_env_name_513_chars_with_extension_fails() {
 }
 
 // ══════════════════════════════════════════════════════════════
-// Bug fix: onEnter is required per spec §4.3
+// Environment actions: at least one of onEnter or onExit (spec §4.3)
 // ══════════════════════════════════════════════════════════════
 
 #[test]
-fn test_env_actions_on_enter_required() {
-    // onExit alone should fail — onEnter is required
-    check_env_err(
+fn test_env_actions_on_exit_only_is_valid() {
+    // onExit alone is sufficient: a queue environment whose only work is
+    // cleanup does not need an onEnter.
+    decode_ok(
         r#"{
         "specificationVersion": "environment-2023-09",
         "environment": {"name": "Foo", "script": {"actions": {"onExit": {"command": "cleanup"}}}}
     }"#,
-        &["environment -> script -> actions:\n\tonEnter is required."],
+    );
+}
+
+#[test]
+fn test_env_actions_on_enter_only_is_valid() {
+    decode_ok(
+        r#"{
+        "specificationVersion": "environment-2023-09",
+        "environment": {"name": "Foo", "script": {"actions": {"onEnter": {"command": "setup"}}}}
+    }"#,
+    );
+}
+
+#[test]
+fn test_env_actions_empty_is_rejected() {
+    // Removing the onEnter requirement must not make an empty actions object
+    // acceptable.
+    check_env_err(
+        r#"{
+        "specificationVersion": "environment-2023-09",
+        "environment": {"name": "Foo", "script": {"actions": {}}}
+    }"#,
+        &["environment -> script -> actions:\n\tmust define at least one of onEnter or onExit."],
     );
 }
 

crates/openjd-model/tests/integration/test_wrap_actions.rs

@@ -713,6 +713,31 @@ fn defining_zero_wrap_hooks_accepted() {
     );
 }
 
+// ════════════════════════════════════════════════════════════════════
+// At-least-one-action rule, WRAP_ACTIONS wording
+//
+// An environment script must define at least one action. With
+// WRAP_ACTIONS enabled the error names the wrap hooks as a third
+// acceptable choice alongside onEnter and onExit. The wording without
+// the extension is covered in test_environment_template.rs.
+// ════════════════════════════════════════════════════════════════════
+
+#[test]
+fn empty_env_actions_rejected_with_wrap_hooks_named() {
+    expect_env_err(
+        r#"{
+            "specificationVersion": "environment-2023-09",
+            "extensions": ["WRAP_ACTIONS", "EXPR"],
+            "environment": {
+                "name": "Empty",
+                "script": {"actions": {}}
+            }
+        }"#,
+        WRAP_EXTS,
+        &["environment -> script -> actions:\n\tmust define at least one of onEnter or onExit, or the complete set of wrap hooks (onWrapEnvEnter, onWrapTaskRun, and onWrapEnvExit together)."],
+    );
+}
+
 // ════════════════════════════════════════════════════════════════════
 // EXPR prerequisite (RFC 0008)
 //